Airfoil Data
S1223RTL

The S1223 RTL is a 13.9% chord-thickness airfoil with a maximum camber of 6.9% at 27% chord, suited to high-lift UAV wings, RC sailplanes, and low-Reynolds-number slow-flyers. At zero angle of attack the cambered geometry generates positive lift, giving an estimated zero-lift angle of -6.9°.

Thin airfoil theory predicts a stall angle near 10.9° and a peak lift-to-drag ratio around 71 at typical UAV and light-aircraft Reynolds numbers — useful benchmarks before running a full XFOIL or NeuralFoil polar. The 14% thickness provides structural depth for main-spar placement without excessive drag penalty at moderate speeds.

Designers evaluating the S1223RTL typically compare it against profiles of similar thickness: NACA 2424, GOE 255 (MVA CA.6) AIRFOIL, EPPLER 422 AIRFOIL, GOE 449 AIRFOIL, LIEBECK LA5055 AIRFOIL. The FX 74-CL6-140 is another reference profile frequently considered alongside it.